David Knight
2009-Feb-21 16:42 UTC
[Xen-devel] A question about "suspend-record frame number"
Dear friends: in xc_domain_save.c, there is a suspend-record frame number which is stored in the first vcpu''s edx register. What the major use of this "suspend-record frame number". Why this frame number is store there? I want to replace the suspend_and_state with xc_domain_shutdown because the former one is much slower. But after I replaced the funcion, that frame number was lost. What if I ignore the error and omit the corresponding code in xc_domain_restore.c?? Thanks. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Feb-22 04:43 UTC
Re: [Xen-devel] A question about "suspend-record frame number"
The suspend-record provides information from the suspended guest to xc_domain_save/restore in the toolstack, and then back to the restored guest. You can''t just do xc_domain_shutdown() from the tools because a PV guest has to prepare itself for save/restore, and it wouldn''t get the chance to do that in that case. The suspend_and_state() got sped up a lot for guests which support suspend notification via an event channel (rather than going via xenstore, which is 100s of milliseconds slower typically). -- Keir On 21/02/2009 08:42, "David Knight" <dongwei.net@pku.edu.cn> wrote:> Dear friends: > > in xc_domain_save.c, there is a suspend-record frame number which is > stored in the first vcpu''s edx register. What the major use of this > "suspend-record frame number". Why this frame number is store there? > > I want to replace the suspend_and_state with xc_domain_shutdown because > the former one is much slower. But after I replaced the funcion, that > frame number was lost. What if I ignore the error and omit the > corresponding code in xc_domain_restore.c?? Thanks. > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel